Centrifugal basket and lining therefor



1930- H. B. JOHNSON 1,770,854 CENTRIFUGAL BASKET AND LINING THEREFOR Filed May 14, 1950 2 Sheets-Shet 1 July 15, 1930. H. B. JOHNSON I v CENTRIFUGAL BASKET AND LINING THEREFOR 2 Sheets-Sheet 2 Filed May 14, 1930 Patented July is, 1930 UNITED STATES- PATENT-OFF! HERBERT n-aonnson. or LAnoHMoN'r, NEW YORK CENTRIFUGAL BASKET AND LINING- THEREFOR Application filed May 14,

The present invention relatlis to filtering apparatus of which centrifugal basket constructions are a type, and to filter media to be used therewith.

In the art offiltering or separating solids from liquids by means of fabric or metallic screen lined centrifuges, great difficulty has been experienced in that due to the tremendous centrifugal force developed in such devices, there is a leakage of solids around the top and bottom edges of the filter cloth, with consequential .loss in filtering efficiency.

This leakage may be due to failure to correctly fit the filter fabric closely and tightly a in place in the perforated centrifugal basket, or unevenness or non-uniformity of height of the fabric. The usual practice is to manually place a filter cloth in position within the centrifugal basket and then retain the same there by means of, internal metallic bands of substantial width overlying the cloth, in conjunction with bolts exanding the bands and clamping'the fabric etween the band and the inner wall of the centrifuge. Such expedients are far from satisfactory, due to the fact that it is difiieult to prevent leakage from the cloth so held and the basket itself. The basket and its accompanyingbolts also throw the centrifuge, ofi alance, which is extremely dangerous when running at'high speed. Fitting and replacement of such arrangements covers a long period of time, requiring expert labor, and due to corrosion of suchnrfallic parts, replacements of. cloths are extremely dithcult.

The principal objects of the invention are. therefore, to provide a filtering apparatus of a construction in which a cloth or fabric may be readily placed or replaced, and in a manner which will produce efiicient filtration with minimum leakageof solids,'and which in a centrifuge will maintain the balance therebf during operation. These and other objects are obtain d with an ap aratus of special design, and by means of a fi ter fabric constructed as hereinafter described.

One aspect of the invention contemplates the provision of a centrifugal basket with an upper and lower circumferential groove 10- 1930. Serial No. 452,288.

cated on the inner face of the baske andaxially' beyond the perforated are thereof. These grooves preferably extend in a direction parallel to the basket axis, although this is not essential. A filter cloth or fabric may then be fitted to the basket interior so as to cover the perforated area, the longitudinal edges thereof lying in the respective grooves of the basket. Wicking or other suitable strip packing may then, be placed in the grooves over-the cloth to seal against-leakage of solids. Upon the development of centrifugal force in the basket, the packing will i tial wire or bamboo strip in proximity to.

the upper and lower edge of the cloth and adapted to lie within the aforesaid grooves. As a further modification, the fabric may have applied to it rows of a liquid or plastic material which upon subsequent treatment will acquire a desired degree 9f stifi'ne'ss or hardness. These rows of hardened material may be on either or both sides of the fabric and in the latter case, bear-ranged at an angle to each'other. These stiffening strips may be either flush with the fabric surface -or project therefrom and where on the busket side of the fabric will serve tospace the filter medium from the basket wall. When on the opposite or exposed side of the fabric, such heads will serve to protect the cloth{ from injury in unloading the cake by reason I of the. fact that thelmloading or scraping blade will contact with the bead rather than the" cloth. The invention contemplates either or both arrangements. 7

The invention further consists in the novel arrangement, combination and construction' of parts, more fully hereinafter described and shown in the accompanying drawings.

In the drawings Fig. 1 is a fragmentary sectional view of a centrifugal basket embodying the invention. Fig. 2 is a fragmentary sectional view of a modified basket.

Fig. 3 is a similar view of still another .form.

Fi 4 is a view of a filter cloth embody- .in t e invention.

a perforated wall of a centrifugal ba et of any desired construction, and mounted for rotation in the usual and well-known manner. It is to be understood that while a centrifugal typeof filter apparatus is shown, yet the invention is applicable'to any t pe of separation equipment utilizing a fi ter cloth or fabric. 'Within this basket a filter cloth 2 of fabric is placed so as to cover the perforated area of the wall and retain the solids thereon, the liquid menstruum passing through the wall, all asis well-known in this art. A mesh screen 2 is usually placed between the filter medium and the basket wall 85 to space the two apart and permit escape of the liquid through the perforated basket wall.

In practicing the invention, it is preferable to provide an upper groove 3 and a lower 1 groove 4 beyond the perforated area, ex-

. thereof are placed in the grooves 3 an respectively. VVicking or other suitable packing 5, preferably of a strip nature, may then tending circumferentially of the basket and substantially parallel to the axis thereof:

In fitting the cloth. to the .basket interior,

the upper and lower longitudinal ed es 4 be used to fill the groovesand completely cover the edges of the cloth 2. This packing may be of a more dense nature in order to insure' the prevention of leakage therethruand around the edges of the filter cloth. Upon rotation of the basket, this packing will-be forced into the groove under cen-'- tnfugal action or-the flowing fluid and tend to more completely seal the edges of the cloth a ain'st leakageof solids-rand thus insure high filtering efiiciency This packing may be'accentuated by arranging the grooves at an angle, somewhat as shown at 6 in Fig. 2.

Centrifugal baskets of usual-construction, to wit, without the grooves of this invention, may be readily supplied with each feature either by actually cutting the. groovesinto e wa her of 1: byproriding asubstan- 'tially circumferential band 7 at the top and bottom of the side wall thereof,

as shown in Fig. 3. Such elements 7 may be within which the edge of the filter cloth may be fitted. The strip 7 may be secured in place by any desired means, such as cement, or by screws or the like 9. Obviously this band may be integral or in'sections to facilitate placing and replacing as desired.

While the broad invention contemplates the use of ordinary filter cloths or fabrics, yet'the efficiency of the device as a whole may be greatly increased, particularly in the time saved by placing and replacing the filter medium, by use of a fabric bearing stifi'ening or spring elements therein or thereon. Such a filter medium is shown in one form to consist of a woven fabric of any desired weave,'in connection with spring elements of wire, bamboo, or other flexible material. Such stripsmay be, and preferably are, woven into the cloth. These spring strips 11 are of a length equal to the distance between the top and bottom grooves. The ends of the-strips may be strun into the grooves, thus carrying the fabric e ges thereinto and holding the fabric in place until the wicking can be placed. Likewise, this construct-ion holds the fabric firmly to the basket walls during the scraping and unloading operations. To remove the cloth, the spring elements are simply sprung out of the groove after removing the wicking.

In addition to the ease of fitting and replacement. of the cloth of the above design, it has the added advantage of being much stronger than one without such strips. It will be apparent that as the retained filter cake builds up, a eater load is placed on the basket by centri gal force. The presence of such stri s aids materially in kee ing the cloth or fabric tightly in place an carry ng the'thus accumulating load.

In another form, thespring elements may be arranged in the longitudinal edges of the clothas in Fig. 6. Here the elements comprise wires 12and are enclosed within a hem 13 of the cloth, and adapted to lie within the grooves, as herebefore. Such a construction lpermits the cloth edges to be rapidl and quic 1y sprung into the. grooves an overlaid with packing.

\Vhen it is not desired to enclose the wires 12 in a hem in the cloth, they may be separate therefrom and in one case lie in a back fold 14 as shown in Fig. 7. This arrangement of parts holds the edges of the cloth firmly against sagging and the wicking seals the same as above described; To remove the fabric thus held, it is only necessary to pull out the strip wicking, slip out the wire and re- 'move the cloth.

The invention contemplates either the overlapping of the ends of the fabr c 50 as to there or,-

applied to the fabric as a liquid or semi-liquid and brought to the desired degree of hardness orstiffness by subsequent treatment. Such a material may be chosen from the wellknown class of substances like bakelite, latex, synthetic resins, various-flexible porcelains,

cements,-superimposed layers of rubber or cement and metallic strips or the like. Such the cloth I and upon subsequent treatment hardeninto a strip, the outer surface of which is flush with the surface of the fabric as at in'Fig. 8, or form a dried up head as at 16 in Fig. 9. This latter figure also shows a series of beads 17 in'the op osite side of the fabric, at an angle to the 16. This not only tends to stiffen the filter one to dispense with the mesh material 2". 'Where the beads of stiffened or hardened material are arranged circumferentially' on the exposed side of the cloth, the unloading knife or scraper in rematerials may be made to actually soak into eads media, but spaces the cloth fromthe basket wall and thus enables I lining tight against the basket walls, the ends only of the spring means extending into the grooves in the basket wall. .5. In combination, a centrifu a1 baske h'aving grooves in the basket wal a lini-ng' therefor, and spring means to maintain the lining tight against the basket walls, said spring means extendin vertically into the grooves at the top and %ottom of the basket walls. j I

6. In combination, a centrifugal basket, a

lining therefor, and spring means to mamtain the lining tight against the basket walls,

ing. a

v7. In combination, a centrifugal basket having a erforated wall, a strap secured within the asket and beyond the perforated portion, a groove in said strip, and a lining Jcgvering the perforated. portion of the basket and extending into said groove.

8. A filtering cloth or media consisting of a tightly wovencloth fabric and spaced a art I spring means woven thereinto and capab e. of maintaining the cloth flat against a tendency tosa In testimony whereof, I have hereunto subscribed my name this 13th day of May 1930. HERBERT B. JOHNSON.-

' moving the cake, may contact therewith and thus prevent damage to the'cloth-in this operation.

' While the invention has been shown and described with particular reference to certain types of filtering apparatus, such as contrifuges, and filtering cloths, yet obviously it is not to be limited thereto, but the invention is tobe construed broadly and restricted 3' -only by the scope of the claims.

I claim 1. In combination, having a peripheral groove, and a lining for the basket walls extendinginto said .an integral portion of the basket "wal overlying the peripheral edge of the lining.

a centrifugal basket oove,

said spring means being woven into the lin- 2. In combination, a centrifugal basket having a: peripheral groove, a lining for the basket w ls extending into said groove, an

. the perip eral edge of the linin means overlying an edge of ti also within'--.the groove.

3. In combination,

' having an interior peripheral groove at the and'pac e limng an riphof the .lining extending into said 4.'In combination, a centrifugal basket;

havin' grooves in the basket wal a, lining integral ortionof the basket wall ove'rl 'ng a centrifugal basket top and an interior perlpheral oove at the eifby-walls inand spring means to ma ntain .the- I 't thebas I 

